1. Field of the Invention
The present invention relates to Schottky transistors, and more particularly Schottky transistors which are adapted for non-saturating operation with relatively low residual voltages at high temperatures.
2. The Prior Art
A Schottky transistor is one in which a planar transistor is combined with a Schottky diode in a common semi-conductor crystal structure, so that the Schottky diode is internally coupled with the planar transistor, to reduced the tendency of the planar transistor to saturate.
According to the principle Baker, when a Schottky "clamp diode" is connected between the base and collector zone of the planar transistor, saturation of the transistor is avoided, and the switching time is made shorter. A Schottky diode is typically used since the diode should have a smaller forward voltage drop then the base-collector-pn-junction of the planar transistor. Unfortunately, because of the manner of construction of conventional Schottky transistors, the external residual voltage is increased. This is generally undesirable, because a large difference in voltage levels must be insured for the two operating states of the transistor. The greater residual voltage also tends to weaken the clamping effect of the Schottky diode, and tends toward a displacement of the operating point in the direction of saturation.